1. Field of the Invention
This invention relates to an improved process for the oxidation of hydrocarbons, particularly aliphatic and alicyclic hydrocarbons, to form the corresponding hydroperoxides. More particularly, the invention relates to an improved catalytic process for the production of alcohols and ketones wherein a hydrocarbon is oxidized in the presence of a molecular oxygen containing gas to produce a reaction mixture containing the corresponding hydroperoxides and the hydroperoxide is decomposed, the products of the decomposition generally comprise the alcohol and ketone. As is well known of the art, the products of such decomposition reactions are employable as obtained as commercial products, for example, tertiary butyl alcohol in the case of the decomposition of tertiary butyl hydroperoxide, or alternatively, may readily be converted by further reaction, as by oxidation, to derivatives thereof, for example, adipic acid, in the case of decomposition of cyclohexyl hydroperoxide producing a mixture of cyclohexanone and cyclohexanol.
2. Description of Prior Art
The oxidation a the number of aliphatic and alicyclic hydrocarbons to end product alcohols and ketones, optionally via hydroperoxide decomposition, is a well-known competitive, large-volume industrial practice. Experience in the operation of such processes, which are reflected in the disclosures of numerous patents and literature references, has indicated that the oxidation must be carried out at controlled conversion levels, for example, to minimize the formation of other undesirable oxidation products, some of which may have an adverse effect on acceptability in industrial usage directly or may have deleterious effects in the production of derivative products and/or of purity of the derivative products produced. Relatively minor process improvements, such as in the yield of the intermediate hydroperoxide, or in the conversion of the hydroperoxide to desired alcohol and ketone product, may result in highly beneficial cost advantages. Accordingly, there is a strong economic incentive to increase the efficiency of the oxidation process from which such products are obtained.
In U.S. Pat. No. 3,879,467 there is disclosed a process for the catalytic oxidation of certain hydrocarbons utilizing an organic hydroperoxide in the presence of a chromium catalyst to produce alcohols and ketones as the primary products. Also disclosed in this patent for this purpose are a number of other specific metal catalysts which resulted in low hydroperoxide conversions or low product yields, or both, or in instances where high conversions were noted, almost no product yields were obtained.
U.S. Pat. No. 3,530,185 discloses a process for the partial oxidation of cyclohexane employing a mixture of gases including molecular oxygen at controlled partial pressure and inert gas in the presence of a catalyst, such as a cobalt compound, which will cause decomposition of the intermediate cyclohexyl hydroperoxide to cyclohexanol and cyclohexanone.
U.S. Pat. No. 3,987,100 discloses cyclohexane oxidation in the presence of a binary catalyst system comprising specific amounts of chromium and cobalt to produce cyclohexyl hydroperoxide followed by decomposition thereof in the presence of said catalyst and recovering a product of cyclohexanone and cyclohexanol in specified ratio.
U.S. Pat. No. 3,925,316 discloses a process for the preparation of mixtures of cycloalkanols and cycloalkanones by heating cycloalkyl hydroperoxides in the presence of a soluble derivitive of ruthenium.
Certain forms of ruthenium have also been reported in recent publications in connection with cumene hydroperoxide decomposition studies. In this regard, attention is directed to "Use of the Proton NMR Relaxation Method to Study the Coordination of Cumene Hydroperoxide With Cobalt and Ruthenium Carboxylates", V. M. Nekipelov, Dokl. Akad. Nauk SSSR, V 261 (6), 1377-81 (1981); "NMR Studies of .Mu3-Oxotriruthenium Hexacarboxylate Cumene Hydroperoxide Interaction", A. M. Trzeciak, Oxid. Commun., V. 1 (4), p. 295-303 (1980); "Cumene Hydroperoxide Decomposition Reaction Catalyzed by Ruthenium (III) beta.-diketonates", A. M. Trzeciak, et al, React. Kinet. Catal. Lett., V. 12 (1-2), p. 121-5 (1981); and "Decomposition of Organic Hydroperoxides on Ruthenium .pi.-Complexes", Yu A. Aleksandrov, Ah. Obshch. Khim., V. 48 (9), p. 2142 (1978).
A significant step in the rather complicated overall oxidation process is the decomposition of the hydroperoxide, which is the subject of our co-pending application Ser. No. 462,261, filed of even date, entitled "Decomposition of Hydroperoxides in the Presence of Homogeneous Binary Catalysts", the disclosure of which is hereby incorporated by reference. Since the efficiency of the decomposition step contributes to the efficiency of the overall oxidation step, improvement in the decomposition of the hydroperoxide is an obvious desirable objective.
As is apparent to those skilled in the art, the hydroperoxide decomposition may be effected in various manner. Hence, the hydroperoxide may "self decompose", in which case all of the alcohols and ketone moieties produced are derived directly from the hydroperoxides. Alternatively, in the event a diluent and/or solvent is employed in the decomposition reaction, the hydroperoxide may also decompose by a reaction involving the hydrocarbon diluent/solvent which is converted to alcohol and ketone products. Under these circumstances the process is represented as being the reaction of one mole of the hydrocarbon starting material with one mole of the corresponding hydroperoxide to yield two moles of alcohol and/or ketone. In addition, since there is a build-up of liberated molecular oxygen as a result of decomposition of hydroperoxide, additional oxidation of the hydrocarbon diluent/solvent may be anticipated as a result of reaction of such liberated oxygen therewith.
The reaction of the diluent/solvent hydrocarbon results in higher conversions, in general, of the hydrocarbon starting material to the useful oxidation products that will be realized if the hydroperoxide decomposed by itself. Of particular advantage would be to increase the amount of alcohol and ketone product derived from the diluent/solvent by its oxidation with the hydroperoxide or liberated oxygen, without adversely affecting the yield of alcohol and ketone derived directly from the intermediate hydroperoxide.
Accordingly, improvements in the oxidation step as well as in the decomposition step of the process for producing alcohols and ketones from hydrocarbon feed materials are highly desirable objectives.